Races
Fun Trails Chichibu & Okumusashi
Japan, November. 100 mi on 75% trail. +36,844 ft of climbing. 32 hours cutoff.
- Start968 ft
- High2,917 ft
- Low263 ft
- Finish971 ft
- Japan at mile 0.0
- Fun Trails Chichibu & Okumusashi mile 20 at mile 20, cutoff 6.4 hours
- Fun Trails Chichibu & Okumusashi mile 40 at mile 40, cutoff 12.8 hours
- Fun Trails Chichibu & Okumusashi mile 60 at mile 60, cutoff 19.2 hours
- Fun Trails Chichibu & Okumusashi mile 80 at mile 80, cutoff 25.6 hours
- Finish Japan at mile 100, cutoff 32 hours
Geometrycourse math
Weather at the cruxcourse math
At hour 8 of race, feels like 20 C (66 F).Sample of 7 race days, medium confidence.At hour 8 of race, apparent temperature P90 is 20 C / 68 F.
The cruxHumid climbs, ridge exposure, and aid gaps in remote terrain (near mile 65)
Course DNA
The Course
Fun Trails Chichibu & Okumusashi runs 100 mi through Japan. +36,844 ft gain and -36,841 ft loss. Surfaces skew 75% trail / 20% dirt road / 5% paved. Humid climbs, ridge exposure, and aid gaps in remote terrain. High point near 3,169 ft. Low near 246 ft. November temps run 50°F to 85°F. The course rewards patience early and punishes rushed descents after mile 50.
The Work
Train for 36,844 feet of climbing across 100 mi. Back-to-back long runs on trail. Practice power-hiking grades above 15 percent. 32 hours total means limited margin: rehearse fueling every 45 to 60 minutes and downhill eccentric work weekly. Technicality 5/10. Build a block that simulates the crux near mile 65.
Kit
November in Japan: plan for 50°F to 85°F. Mandatory shell if rain is in forecast. Headlamp with spare batteries if 32 hours pushes past dark. Poles help on sustained climbs above mile 25. Vest capacity for 2 liters minimum. Shoes matched to 75% trail: lugs for mud, rock plate if the course turns technical after mile 50.
Race Day
Hold effort through mile 25. The field often splits on the first big climb after mile 50. Humid climbs, ridge exposure, and aid gaps in remote terrain near mile 65 is where time is won or lost. Walk the steep pinches. Run the flats and gentle downhills. Crew at major aids: socks, calories, ice if hot. Transitions under 5 minutes when possible. Final third is 33 miles of fatigue management. Finish with reserve for the last descent.
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